[USER (data scientist)]:Please filter the dataset to include only main course items such as sandwiches, wraps, and salads, and exclude side dishes and desserts. Then, provide the filtered dataset containing only main course items. Please load the 'fastfood.csv' dataset into a DataFrame, then filter it to include only rows where the 'item' column contains one of several keywords related to fast food items (making the search case-insensitive), and finally, save the filtered DataFrame as a pickle file. 
My template of code snippet is:

---BEGIN CODE TEMPLATE---
import pandas as pd
import numpy as np
import pickle

atp_tennis = pd.read_csv('atp_tennis.csv')

# YOUR SOLUTION BEGIN:
<code1>
[COMPLETE YOUR CODE]  
</code1>
# YOUR SOLUTION END 

print(federer_match_ids)
pickle.dump(federer_match_ids,open("./pred_result/federer_match_ids.pkl","wb"))
---END CODE TEMPLATE---

[YOU (AI assistant)]: